It is true that modern society is the most sinful ever.
But this is misunderstood because 'sin' is misunderstood.
To say that modernity is sinful without previous equal does nor mean that modern people commit more sinful acts than ever before.
I do not think this is true; and anyway it is impossible to establish; or perhaps even meaningless to quantify and calculate numbers and severity of sinful acts.
When sin is recognized as a perspective or orientation, then the statement that modern society is the most sinful ever becomes clear - and obviously correct.
Sin is to be orientated away from God; and modern society is exactly that.
Modern society does not believe in transcendental reality; does not believe in the soul; does not believe in life after death; does not believe in any kind of God; does not believe in a personal God - concerned by individual salvation; and does not believe that Jesus was the incarnate Son of God.
That is to say that modern society, in its public discourse, excludes (and implicitly at least, often explicitly) the reality of any other than the material.
That is to say that modern society is not capable of the kind of relationship to reality of the ancient Greeks (who believed in transcendent reality, and in an impersonal God); nor are we animistic - like hunter gatherers; nor pagan; nor monotheistic; and certainly not Christian.
Modernity cannot be Christian since modernity lacks all the simpler, more basic orientations to which Christianity historically was added, which Christianity historically completed.
This is why modernity is the most sinful of all human societies - not from what we do, but from our social orientation.
Modernity is turned-away from Jesus, of course, and turned-away from any conception of God - and not only from God but from all the other transcendent realities of every previous society.
Not only is modernity turned-away from transcendent reality, modernity is turned-away from reality: denies that reality is any other than an arbitrary social construct; and denies the existence of anything other than the immediate material world.
In other words, modernity is nihilist - not superficially nihilist at the level of conscious and explicit claims or statements; but denying of the reality of the real at the deepest level of assumption and action.
Indeed more even than this: it is not just denial, but incomprehension. Modernity does not even comprehend that reality could be real - it does not know what this means.
Modernity is without any doubt the most sinful society ever - not just because it denies vitrue (which it does) nor even because it embraces sin (which it does), but because it cannot even comprehend the meaning of sin.
Note: Modern scientists believe this nihilism as much as everyone else - modern scientists implicitly believe (as demonstrated by their actions) that scientific 'reality' is defined by peer review, that is by a consensus of experts. They believe that the process of peer review can be shaped to yield a result, then that result is regard as scientific truth - the meaning of 'sceintific truth' is not that it is reality, but that other people should defer to it.